Determining how many and what type of people are viewing which television programs helps television program producers improve their shows and determine a price for advertising slots during those shows. In addition, accurate television viewing demographics allow advertisers to target certain types and sizes of audiences. Similarly, radio listening demographics are also useful to producers and advertisers.
To collect these demographics, an audience measurement company, such as Nielsen Media Research, may enlist a plurality of television viewers, radio listeners, and/or any other type of audience member. The habits of the enlisted audience members are collected to statistically determine the demographics of the audiences and to develop ratings of those programs. Surveys may be used, but automatic measurement systems are preferred because of the increased accuracy of the statistics and the convenience for the viewers.
One aspect of automatic viewer measurement systems is to record information used to determine what television program is showing on a television or playing on a radio. Many automatic viewer measurement systems are non-invasive systems, which do not require installation of circuitry within the television or radio. Instead, external devices are used to determine what television program is showing or what radio program is playing. In contrast, invasive measurement systems install circuitry within the information presenting device (e.g., TV, radio, etc.) of the audience member. Invasive techniques are less desirable because of the possibility of damage to the information presentation device.